Prepared atmosphere made in a heated generator where natural gas and air, about 2.5 parts air to 1 part methane, react over a nickel catalyst. The product is roughly 40 percent hydrogen, 20 percent carbon monoxide and 40 percent nitrogen, the standard carrier for carburizing, carbonitriding and neutral hardening. Carbon potential is trimmed with enriching gas or dilution air, and generator dew point is the operator's quick check.
Endo generator's running a plus 40 dew point, carbon's going to stay low until somebody burns out the catalyst.
Endo is about 20 percent carbon monoxide, which has no smell, so heat-treat shops run fixed CO monitors around generators and furnaces.
Also heard as
- endo
- endo gas
- endogas
- RX gas
Related terms
Carbon potential
The carbon content a furnace atmosphere would give the surface of plain steel at equilibrium.
Dew point
The temperature at which water vapor in a furnace atmosphere condenses, used as a gauge of carbon potential.
Integral quench furnace
A sealed batch furnace with a heating chamber and an attached oil quench, run under protective atmosphere.
Sooting
Free carbon depositing in a furnace or on parts when the atmosphere carries more carbon than it can hold.